HIGH PERFORMANCE POLYMERS
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2021
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IF 2.161
Dandan Li,Chengyang Wang,Shengqi Ma,Hongwei Zhou,Ran Lu
To prepare soluble polyimides with high temperature resistance, two new diamine monomers, namely, 2,2′-(4,4′-oxybisphenylene)-bis(1-phenyl-5-aminobenzimidazole) (5a), and 2,2′-(4,4′-hexafluoroisopropylidene)-bis(1-phenyl-5- aminobenzimidazole) (5b), were synthesized and exploited to prepare three series of poly(benzimidazole imides)s (PBIIs) by a conventional two-stage synthesis. The resulting PI films were flexible and tough, possessing high glass-transition temperatures (Tgs = 311°C–390°C), improved optical transparency, and excellent solubility. Moreover, the effect of different configuration on performance was revealed, and these data provided a feasible method to enhance both Tg and solubility of PIs by incorporating N-phenyl benzimidazole and corresponding functional moieties.
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ENVIRONMENTAL RESEARCH
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2021
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IF 6.498
Jiayi Li,Ying Huang,Minhua Su,Yuying Xie,Diyun Chen
Heterocyclic aromatic compounds such as malachite green can cause immense harm to the environment and mankind because of their toxic bio-accumulation and insufficient biodegradation. ZnFe 2 O 4 /TiO 2 (ZF-T) has attracted attentions as a visible-light-driven catalyst because it can break and mineralize benzene through photolysis. Compared with TiO 2 , which photodegrades only 53.5% malachite green, anatase TiO 2 loaded with ZnFe 2 O 4 has greater photocatalytic activity and can degrade up to 90.1% malachite green. Furthermore, a photocatalytic efficiency above 80% can be obtained through five consecutive cycles with a duration of 4 h. In this study, ZF-T was characterized, and its photolytic parameters, including dosage, pH, time, and ionic strength, were optimized. The photolytic products of malachite green were analyzed by ultraviolet–visible spectroscopy and liquid chromatography-mass spectrometry, which confirmed that ZF-T can drive visible light to produce •O 2 − and H + free radicals that can efficiently degrade heterocyclic aromatic hydrocarbons and cleave benzene rings. These outcomes deepen our understanding of the development and applications of visible-light-driven ZF-T composites in the field of wastewater purification.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Liting Xu,Yuhong Lv,Xingwei Li
The commercial development of direct methanol fuel cells (DMFCs) has been hampered by Pt anode catalysts with a high cost, and its long-term stability is also unsatisfactory, especially in acidic media. Therefore, the development of catalysts with high efficiency and low cost is an urgent problem. To reduce costs, a simple solution is to use non-precious transition metals to partially replace precious metal Pt. Moreover, the catalyst supports are also crucial in term of stabilizing and dispersing Pt-based catalysts. Herein, N-doped carbon-stabilized Pt 3 Co catalyst (Pt 3 Co/NC) is successfully prepared via the pyrolysis of Pt-encapsulated Co/Zn-based zeolitic imidazolate frameworks (Pt@ZIF-8/67). And catalytic performance of Pt 3 Co/NC catalyst is studied in 0.5 M H 2 SO 4 solution containing 0.5 M CH 3 OH. The area specific activity of Pt 3 Co/NC catalyst is 1.15 mA cm −2 Pt, which is about 4 times as great as that of commercial Pt/C. Furthermore, the as-prepared catalyst also shows better stability compared to Pt/C.
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ACS Catalysis
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2021
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IF 13.084
Muhong Li,Shanyong Chen,Qike Jiang,Qingliang Chen,Xuan Wang,Yong Yan,Jian Liu,Changchang Lv,Weiping Ding,Xuefeng Guo
The production of functionalized anilines by chemoselective hydrogenation of nitroarenes occupies an important position in the chemical industries. Recently, cobalt and nitrogen codoped carbon (Co–N–C) catalysts have been reported to show outstanding catalytic performance in this process, whereas the nature of their active sites is still at the center of intense debate. In this paper, based on the well-controlled experiments on four types of typical Co–N–C materials derived from different methodologies, several unusual generalities in the hydrogenation of nitroarenes are clearly revealed, including protic-solvent dependence, antipoisoning, acid resistance, and reversible deactivation. Further investigations indicate that the single-atom species Co–Nx are the main active sites of the Co–N–C catalysts in this chemoselective hydrogenation process. The present work sheds light on the mechanism study on the metal–N–C catalysts and further contributes to the rational design of the high-performance single-atom catalysts.
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JOURNAL OF SUPERCRITICAL FLUIDS
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2021
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IF 4.577
Jian-Lei Qi,Qin-Qin Xu,Dan Zhou,Jian-Zhong Yin,Qi-Ke Jiang
Cu single atoms dispersed on N-doped carbon materials (Cu-NC) were obtained after supercritical CO 2 deposition and decompression, without further post-treatment. AC-HAADF-STEM, STEM , XRD , ICP-OES, and XPS results confirmed that the Cu atoms were equably dispersed over the N-doped carbon (NC) support with the loading of 0.80 wt%. The catalytic performance of Cu-NC in solvent-free oxidation of phenylcarbinol to benzaldehyde was investigated, and the conversion of 73.9% and selectivity of 85.7% were obtained at 50 °C for 1 h. A high-pressure view cell was used to observe the dissolution and diffusion for Cu(acac) 2 in scCO 2 . The stability of Cu-NC structures and the formation path of active oxygen species (O*) on different configurations were predicted by density functional theory (DFT) calculations, and CuN 3 C 1 was found to be more conducive to the activation of tert-butyl hydroperoxide (TBHP).
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POLYMER
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2021
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IF 4.43
Ying Xiao,Zhao-Yang Wang,Shi-He Luo,Jian-Yun Lin,Xi-Ying Cao,Yong-Gan Fang
Polylactic acid (PLA) is highly attractive polyester in biomedical application, and its thermosensitive materials can achieve multiple functions due to their being sensitive to the temperature. In this work, based on lactic acid (LA), maleic anhydride (MAH), and N -isopropyl acrylamide (NIPAM), a thermosensitive modifier, the thermosensitive PLA material PLAMN is directly synthesized via one-pot preparation of melt polymerization and radical polymerization . The molecular structure, thermosensitive characteristics, and micellization behavior of the serial PLAMNs with different molar feed ratios are well characterized with FTIR, 1 H NMR, GPC , DLS , TEM and other characterization techniques. The results show that, as anticipated, the obtained products have the ability to self-assemble. The specific physical and chemical properties can be controllable by the molar feed ratio n (LA)/ n (MAH)/ n (NIPAM). When the ratio is 20/1/7, the obtained PLAMN 7 has the minimum critical micelle concentration (only 4.17 mg L −1 ), and its critical phase transition temperature is 30.6 °C. This new synthetic strategy can effectively simplify the preparation of the thermosensitive PLA polymeric material, which is beneficial to realize the loading of the hydrophobic drugs.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
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IF 8.128
Xiaoqing Lei,Lijin Huang,Ke Liu,Lei Ouyang,Qin Shuai,Shenghong Hu
Developing high-performance materials for the efficient removal of pharmaceutical contaminants from polluted water has gained tremendous attention but is still a huge challenge. Herein, various N -doped porous carbons (NPCs) were fabricated via a facile and solvent-free pyrolysis strategy by using a mixture of melamine , hexamethylenetetramine , Pluronic F 127, and ZnCl 2 as precursor. The resulting NPCs featuring large specific surface areas (803–1002 m 2 /g) and high nitrogen content (3.79–5.24%) were used as efficient adsorbent for the capture of ibuprofen (IBP) from water. Due to the combination of abundant mesoporous and microporous structure as well as high nitrogen content, the adsorption equilibrium was achieved within 60 min and the adsorption capacity was calculated to be 113 mg/g. Furthermore, it was found that the adsorption capacity exhibited a good correlation with the nitrogen content. In addition, the adsorption capacity of the resulting NPC was well-maintained even after 4 cycles due to its superior stability. The study is expected to encourage the rational design and synthesis of versatile heteroatom-doped porous carbons for practical application in the field of environmental remediation.
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Journal of Materials Chemistry B
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2021
·Vol. 9
·期 23
·4690-4699
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IF 6.331
Xue Wang,Shengxu Qian,Dongdong Wang,Cunli Wang,Haijuan Qin,Lang Peng,Wenqi Lu,Yahui Zhang,Guangyan Qing
Sialic acids located at the terminal end of glycans are densely attached to cell surfaces and play crucial and distinctive roles in a variety of physiological and pathological processes, such as neural development, cell–cell interactions, autoimmunity and cancers. However, due to the subtle structural differences of sialic acid species and the complicated composition of glycans, the precise recognition of sialylated glycans is difficult. Here, a fluorescent dynamic response system based on a pyrene-conjugated histidine (PyHis) supramolecular gel is proposed. Driven by π–π stacking and intermolecular hydrogen bonds, PyHis exhibits a strong self-assembly ability and forms stable gels. It is found that introduction of N-acetylneuraminic acid (a typical sialic acid) can prevent this self-assembly process, whereas other monosaccharides or sialic acid analogs have no significant effect on it. Interestingly, a sialylated glycan also has a remarkable inhibitory effect on the gel formation, which highlights the high selectivity of the gel dynamic response system. Analysis of the mechanism reveals that the sialic acid or sialylated glycan can interact closely with two PyHis molecules stacked together in the assemblies via hydrogen bonding interactions, thereby preventing the ordered accumulation of the gelators. It is worth noting that the high-efficiency sialic acid recognition effect is not observed at the single molecule level but at the supramolecular level, indicating the unique superiority of the supramolecular self-assembly system in biomolecular recognition and response. This work shows the promising prospects of using supramolecular gels in assembly engineering, regenerative medicine, tumour cell sorting and cancer diagnosis.
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JOURNAL OF MATERIALS RESEARCH
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2021
·Vol. 36
·期 6
·1250-1261
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IF 3.089
Lin Zhilan,Zhu Jianhui,Zhang Peixin,Deng Libo
Abstract Spherical carbonaceous materials are considered as ideal electrode materials for supercapacitors because of their high electrical conductivity and excellent electrochemical and mechanical stability. However, their overall performances are yet to be enhanced to meet the future demands. Herein, we prepared a supercapacitive carbon microsphere with hierarchical porous structure and doped them with both nitrogen and phosphor. This was achieved by a facile hydrothermal treatment of cyclodextrin, followed by pyrolysis in the presence of ammonium dihydrogen phosphate and finally by KOH activation. Benefiting from the porous microspheres structure, large surface area, and rich nitrogen and phosphorus heteroatoms, the as-prepared materials demonstrated excellent capacitive performance, with a specific capacitance of 182 F g −1 at 1.0 A g −1 and good rate performance as well as 100% retention after repeated charging and discharging for 5000 cycles, which are superior to the carbon microspheres without heteroatom doping. Graphic abstract
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APPLIED SURFACE SCIENCE
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2021
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IF 6.707
Jianfei Xiao,Yuan Wang,Tian C. Zhang,Shaojun Yuan
Nitrogen-sulfur codoped porous carbon (NSPC) is a promising advanced material, showing great application potential in greenhouse gas capture and energy storage. Here, a novel NSPC with controllable porous structure was fabricated via pyrolysis and activation of N, -containing polycondensates, which were synthesized by one-pot polycondensation reaction of triglycidyl isocyanurate, glucose and thiourea. The obtained sample NSPC-1-650 showed cross-linked spherical morphology with uniform pore size (2.61 nm), large specific surface areas (1927.46 m 2 ·g −1 ), and the doping of nitrogen (4 wt%) and sulfur (2 wt%), which leaded to a good CO 2 adsorption capability (5.56 mmol·g −1 at 298.15 K, 5 bar) and excellent stability. Additionally, when used as a supercapacitor, the NSPC-1-650 sample showed an ultrahigh specific capacitance (224.3F·g −1 at 1 A·g −1 in 6 M KOH electrolyte), an excellent rate capability, and good stability (retained > 85% capacity after 5000 cycles). Notably, the all solid-state symmetrical NSPC-1-650-based supercapacitors delivered a high energy density (the maximal value = 7.8 Wh·Kg −1 ) and power density (the maximal value = 4500 W·Kg −1 ). These results suggest that NSPC-1-650 be a competitive candidate as a CO 2 adsorbent and supercapacitor.
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Catalysts
·
2021
·Vol. 11
·期 5
·561
·
IF 4.146
Fangyuan Wang,Yu Liu,Zhiling Song,Zhichao Miao,Jinping Zhao
Electrochemical CO2reduction reaction (CO2RR) is eliciting considerable attention in relation to the carbon cycle and carbon neutrality. As for the practical application of CO2RR, the electrocatalyst is a crucial factor, but, even so, designing and synthesizing an excellent catalyst remains a significant challenge. In this paper, the coordination compound of Ni ions and dimethylglyoxime (DMG) was employed as a precursor to modify reduced graphene oxide (rGO) for CO2RR. The textural properties and chemical bonds of as-obtained rGO, N–C–rGO, Ni–rGO, Ni–N–C, and Ni–N–C–rGO materials were investigated in detail, and the role of Ni, N–C, and rGO in the CO2RR were researched and confirmed. Among all the catalysts, the Ni–N–C–rGO showed the optimal catalytic activity and selectivity with a high current density of 10 mA cm−2and FE(CO)% of 85% at −0.87 V vs. RHE. In addition, there was no obvious decrease in activity for 10 h. Therefore, the Ni–N–C–rGO is a promising catalyst for CO2RR to CO.Keywords:metallic Ni;N-doped carbon;reduced graphene oxide;electrocatalyst;electrochemical CO2reduction
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2021
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IF 4.098
Li Li,Feng Xu,Ge Sun,Mingrui Sun,Shoushi Jia,Hongmei Li,Tao Xu,Honglian Zhang,Yan Wang,Yue Guo,Taohua Liu
The objective of this study was to establish a novel method for the determination of N-methylaniline (NMA) based on azo coupling reaction in infant pacifiers prepared with food contact silicone materials by combining thin layer chromatography (TLC) with surface-enhanced resonance Raman scattering (SERRS). TLC was used to separate the azo reaction products to confirm the component spot of azo compound, then the spot of azo compound mixed with silver sol on the TLC plate was qualitatively detected by SERRS. The limit of detection (LOD) of the method is as low as 0.50 ppm for NMA. The influence of sample matrix about the TLC-SERRS detection of NMA was investigated by experiment of simulated positive sample, and the NMA in infant pacifiers exposed to silica gel products was detected. The method of TLC-SERRS for the determination of NMA in infant pacifiers prepared with food contact silicone materials was established, and the real samples were detected. Compared with the methods ever reported, the method has the advantages of high sensitivity, specificity and low cost. It provides a new reference method for establishing a safety system for food contact silicone materials.
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危险品化学品经营许可证（带存储）